CSIG-21. TITLE: INTEGRATIVE TRANSCRIPTOME PROFILING OF EXOSOME AND TISSUE IDENTIFIES PROGNOSTIC GENES AS THERAPEUTIC TARGETS OF GLIOBLASTOMA

Abstract For glioma, molecular genetic analysis has grown in significant amounts for disease diagnosis and pathogenesis research. Due to limitations of tissue samples, liquid biopsy is being considered as a substitute for tissue biopsy which can be developed as a diagnostic technique. Studies have demonstrated that exosome-carrying molecules can foster a milieu that is favorable to cancer growth and therapy resistance. METHODS: In the present study the tumor tissue and serum of the same 80 patients were collected with a confirmed diagnosis of glioma with prior consent. Demographic details, pathology reports and survival data were also collected. RNA-seq analysis was performed in both tumor tissue and exosomal RNA. Fastq file with 100bp paired end reads were generated. Raw reads were trimmed using Trimmomatic (Version 0.39) to remove adapter sequences and low-quality reads. Reads mapping to ribosomal RNA were removed using SortMeRNA tool. Trimmed reads were then mapped to the human reference genome GRCh38.d1.vd1.fa using a two-pass method with STAR (2.7.10a). Differential gene expression was performed using DESeq2. The gene ontology and pathway analysis were performed using open source tool PANTHER. RESULTS: The differentially expressed genes shared between tumour tissue RNA and exosomal RNA experiments were selected for further analysis. Genes such as EGFR (tissue: Fold change (FC)[6.1], exosome: FC[7.2]; p-value< 0.001), PDFGRA (tissue: FC[3.7], exosome: FC[5.2]; p-value< 0.001), TTN (tissue: FC[12.6], exosome: FC[11.3]; p-value< 0.001) were found to be differentially regulated and were prominently associated with Integrin signaling pathway, Synaptic vesicle trafficking pathway, Wnt signaling and cellular proliferation. As per literature and clustering analysis, we found that these pathways and genes play an important role in the progression of tumors which can be further integrated into diagnostic platforms. CONCLUSION: This study will provide a reliable and effective way of diagnosis and management of glioma in patients with minimal invasion.